Identification of Guanine-Quadruplex-Binding Peptides from the RGG3 Domain of TLS/FUS

Area of Science:

• Biochemistry
• Molecular Biology
• Medicinal Chemistry

Background:

• Guanine quadruplexes (G4s) are non-canonical nucleic acid structures implicated in various biological processes.
• G4s are recognized as promising therapeutic targets.
• Peptides from G4-binding proteins offer selective G4 recognition platforms.

Purpose of the Study:

• To investigate the G4-binding capacity of arginine-glycine-glycine (RGG)-rich sequences derived from the RGG3 domain of TLS/FUS.
• To evaluate the G4-binding affinities of synthesized RGG peptides.
• To explore the impact of conformational constraints using (E)-methylalkene dipeptide isosteres (MADIs) on G4 recognition.

Main Methods:

• Synthesis of a peptide library of overlapping 15-mer RGG sequences.
• Evaluation of G4-binding affinities using binding assays.
• Generation and assessment of RGG peptidomimetics incorporating MADIs.

Main Results:

• Several native RGG peptides demonstrated measurable affinity for G4 RNA structures, with STK5-1 showing the highest affinity.
• RGG peptidomimetics with MADIs exhibited enhanced G4-binding affinity and selectivity compared to native peptides.
• Sequence and structural features governing G4-binding were elucidated.

Conclusions:

• RGG-rich peptides, particularly STK5-1, show potential for G4 RNA recognition.
• MADI modification can enhance the affinity and selectivity of RGG-based G4 ligands.
• These findings provide a basis for developing novel peptide-based G4 therapeutics.